A collimator or scattering collimator is to be gathered, for example, from DE 100 11 877 C2. The collimator is arranged in a detector arrangement of a computer tomograph. The collimator plates are arranged here in a radial direction relative to an X-radiation source of the computer tomograph, and serve to reduce or suppress scattered radiation that deviates from the radial direction, and is thus not aligned in a radial direction relative to the radiation source.
Collimators and computer tomographs with built-in collimators are further to be gathered from DE 197 53 268 A1 and DE 101 58 021 A1 for example.
The collimator plates, usually metal plates with a high absorptive power for X-radiation, are held in the collimator in a holder. In accordance with DE 100 11 877 C2, the collimator has an upper housing part and a lower housing part between which the collimator plates are arranged. Slot-like openings into which the collimator plates engage are worked into the two housing parts.
Guides on the housing parts are also provided for the end faces of the collimator plates. The collimator plates are fixed in their position by the worked-in slots and the guides. The housing parts are usually constructed from plastic injection-molded parts.
Imaging by use of the computer tomograph requires collimator plates to be positioned highly precisely and exactly in the prescribed position in a radial direction relative to the radiation source. This requires the housing parts to be constructed as high-precision plastic injection-molded parts. Particularly in the case of long collimator plates, however, there is the problem that because of the nature of the production of plastic injection-molded parts the slots and the webs arranged between neighboring slots can no longer be fabricated with sufficient positional accuracy, or that the required high-precision construction can be implemented only with a considerable cost-intensive outlay. Because of the material elasticity, the generally thin-walled webs are, moreover, unstable and of low rigidity.